Unveiling biodegradation mechanism of phoxim: Novel metabolic pathway, functional gene, detoxification effect, and widespread distribution of phoA

IF 9.7 1区环境科学与生态学 Q1 ENVIRONMENTAL SCIENCES

Environment International Pub Date : 2025-09-22 DOI:10.1016/j.envint.2025.109809

Qian Li , Mingliang Zhang , Jiawen Zhu , Hongfei Liu , Gang Hu , Junqiang Hu , Kaihua Pan , Jiandong Jiang , Qing Hong

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引用次数: 0

Abstract

Phoxim, an organophosphorus insecticide (OP), poses risks to non-target organisms in the environment. However, the biodegradation mechanism of phoxim was not fully understood. In this study, a novel detoxification pathway for phoxim in Delftia lacustris PX-1 was identified. A gene cluster pho (phoABC1C2DEFGHI), located on the plasmid, was found to be involved in phoxim degradation. The genes phoA, phoB, and phoD, which were responsible for converting phoxim to benzoate, were functionally characterized in vitro. Notably, PhoA was highly abundant in global cultivated lands. Moreover, acute toxicity experiments showed that both phoxim and its metabolite, 2-hydroxyimino-2-phenylacetonitrile (2H2P), exhibited moderate toxicity to zebrafish, whereas strain PX-1 could detoxify both compounds through degradation. After exposure to 2 mg L⁻¹ phoxim, the brain acetylcholinesterase (AChE) activity levels of zebrafish dramatically decreased by 31.28 % (P < 0.05) relative to unexposed controls. Interestingly, phoxim could promote the colonization of strain PX-1 in the zebrafish gut, which mitigated phoxim-induced damage to AChE activity in the zebrafish brain. In summary, our research reveals a novel phoxim detoxification mechanism and provides a theoretical foundation for the bioremediation of residual phoxim in the environment.

In brief

This study reveals a novel metabolic pathway for phoxim biodegradation and elucidates the detoxification mechanism of strain PX-1 in zebrafish.

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揭示硫磷的生物降解机制：新的代谢途径、功能基因、解毒作用和硫磷的广泛分布

硫辛是一种有机磷杀虫剂（OP），对环境中的非目标生物构成风险。然而，硫辛硫磷的生物降解机制尚不完全清楚。本研究在Delftia lakustris PX-1中发现了一种新的硫辛硫磷解毒途径。在质粒上发现了phoo基因簇（phoABC1C2DEFGHI），该基因簇参与硫辛的降解。在体外对磷硫磷转化为苯甲酸盐的phoA、phoB和phoD基因进行了功能表征。值得注意的是，pha在全球耕地中都非常丰富。此外，急性毒性实验表明辛硫磷及其代谢物2-羟基亚胺-2-苯乙腈（2H2P）对斑马鱼均表现出中等毒性，而菌株PX-1可通过降解对这两种化合物进行解毒。暴露于2 mg L−1硫辛硫磷后，斑马鱼脑乙酰胆碱酯酶（AChE）活性水平与未暴露对照相比显著降低31.28 % （P <； 0.05）。有趣的是，辛硫磷可以促进菌株PX-1在斑马鱼肠道中的定植，从而减轻辛硫磷对斑马鱼大脑中乙酰胆碱酯酶活性的损伤。综上所述，本研究揭示了一种新的硫辛硫磷解毒机制，为环境中硫辛硫磷残留的生物修复提供了理论基础。本研究揭示了一种新的硫辛硫磷生物降解代谢途径，并阐明了菌株PX-1在斑马鱼体内的解毒机制。

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来源期刊

Environment International 环境科学-环境科学

CiteScore

21.90

自引率

3.40%

发文量

734

审稿时长

2.8 months

期刊介绍： Environmental Health publishes manuscripts focusing on critical aspects of environmental and occupational medicine, including studies in toxicology and epidemiology, to illuminate the human health implications of exposure to environmental hazards. The journal adopts an open-access model and practices open peer review. It caters to scientists and practitioners across all environmental science domains, directly or indirectly impacting human health and well-being. With a commitment to enhancing the prevention of environmentally-related health risks, Environmental Health serves as a public health journal for the community and scientists engaged in matters of public health significance concerning the environment.